1. Field of the Invention
The present invention relates to: a method of manufacturing a pneumatic tire having surface fasteners on its tire inner surface; and a pneumatic tire manufactured by the method. Specifically, the present invention relates to a pneumatic tire manufacturing method which improves the productivity of pneumatic tires each having surface fasteners on its tire inner surface, and which avoids manufacturing a pneumatic tire having a deteriorated uniformity, as well as which prevents engagement elements of each surface fastener from being crushed. The present invention also relates to a pneumatic tire manufactured by the manufacturing method.
2. Description of the Related Art
In a pneumatic tire, noise absorbing materials are provided to the inner surface of the tire cavity for the purpose of reducing cavity resonance. The applicant of the present invention has made a proposal on a pneumatic tire having surface fasteners each made of a resin such as nylon or polyester on the tire inner surface so that such noise absorbing materials can be attached to the tire easily (see Japanese patent application Kokai publication No. 2006-44503, for example).
Surface fasteners capable of engaging with the surface fasteners provided to the tire inner surface are also attached to the noise absorbing materials. The surface fasteners attached to the noise absorbing materials are engaged with the surface fasteners provided to the tire inner surface, respectively. This engagement scheme enables the noise absorbing materials to be easily attached to and easily detached as needed from the tire inner surface.
In general, a pneumatic tire of the foregoing type having surface fasteners on the tire inner surface is produced by curing a formed green tire having the surface fasteners beforehand adhered to its inner surface. The pneumatic tire manufacturing method includes a step of deforming a first formed body into a toroidal shape by expansion, the first formed body having been obtained by beforehand adhering an inner liner layer, a carcass layer and the like together on a making drum. In this deforming step, if the surface fasteners each made of a resin such as nylon and polyester are annularly attached to the first formed body which has not yet been deformed by expansion, the surface fasteners can not follow the posterior deformation of the first formed body by expansion, thus falling off from the green tire, since the inner periphery length of the first formed body is extended to a large extent. For this reason, such surface fasteners are attached to the green tire after the first formed body is deformed into the toroidal shape by expansion.
However, the surface fasteners need to be attached to the inner surface of the cavity of the green tire. The attachment requires meticulous work and results in a lower workability. This is a cause of decreasing the productivity. In addition, the surface fasteners are attached to the curved inner surface by hand. This manual work makes it difficult to attach the surface fasteners to the inner surface around an entire circuit of the tire evenly, and inevitably results in deteriorated uniformity.
In general, the green tire is cured in the mold while pressed from its inside by a bladder. As a result, engagement elements of each surface fastener which are exposed to the tire inner surface may be crushed by a pressing force of the bladder. For this reason, measures for this problem are required to be taken as well.